This section provides background information related to the present disclosure which is not necessarily prior art.
Continuous flow grain dryers, such as those shown in U.S. Pat. Nos. 4,404,756, 4,268,971, and 5,467,535, which are incorporated herein by reference in their entirety, generally include two continuously moving columns of grain. One type of continuous flow grain dryer is known in the industry as a “mixed flow” grain dryer. Such grain dryers are commercially available from companies such as Cimbria, NECO, and Grain Handler USA. Other types of continuous flow grain dryers are also available. Each type of grain dryer has its own advantages and disadvantages.
For example, in most types of continuous flow grain dryers air discharged from a fan typically next passes through a burner and then through a grain column only once before being discharged or returned to the blower for recirculation. Recirculated air from volatile grains presents a risk of fire, since it typically needs to pass through the heater during the recirculation process where fines can be ignited. Such single pass airflow through the grain column, and such limitations on the ability to recirculate the air limits the efficiency of the grain drying operation.
One way to attempt to increase efficiency is to cause the heated air to pass through the grain column multiple times. Sometimes this can create challenges for dealing with grain fines within the grain column. For example, some continuous flow grain dryer types might tend to cause the fines to move to a particular position in the grain column (e.g., the edges). Some continuous flow grain dryer types might also recirculate the heated air into grain when the grain has not yet been sufficiently heated to minimize condensation on the grain kernel, which can cause fines to clump, or to stick to the grain dryer walls or diverters.